System and method for containing an emission of sulfur trioxide

ABSTRACT

A system for containing an emission of sulfur trioxide, the system comprising a first pressurized vessel, the first pressurized vessel containing sulfur trioxide, a relief vessel containing a volume of a solvent solution, wherein the solvent solution comprises sulfolane, and a first relief conduit providing a first route of fluid communication between the first pressurized vessel and the relief vessel. A method for containing an emission of sulfur trioxide, the method comprising routing a first relief conduit so as to provide a first route of fluid communication between a first pressurized vessel and a relief vessel, wherein the first pressurized vessel contains sulfur trioxide, wherein the relief vessel contains a volume of a solvent solution, and wherein the solvent solution comprises sulfolane.

BACKGROUND

Sulfur trioxide (SO₃) is a powerful sulfonating agent used industriallyin a variety of processes. However, sulfur trioxide is also recognizedas being hazardous in nature, for instance, being known to reactviolently with water; being corrosive to skin, eyes, mucous membranes,and the respiratory tract; being highly caustic; and being known to fumeor disperse readily in the air. As in any industrial setting whereindustrial chemicals are used, there is the possibility that sulfurtrioxide can be released, either unintentionally (i.e., accidentally orthrough an unintended event) or occurring from the normal operation ofsuch an industrial use.

As such, systems and methods for containing an emission of sulfurtrioxide from industrial settings where sulfur trioxide can be found oris in use are needed.

SUMMARY

Disclosed herein is a system for containing an emission of sulfurtrioxide, the system comprising a first pressurized vessel, the firstpressurized vessel containing sulfur trioxide, a relief vesselcontaining a volume of a solvent solution, wherein the solvent solutioncomprises sulfolane, and a first relief conduit providing a first routeof fluid communication between the first pressurized vessel and therelief vessel.

Also disclosed herein is a method for containing an emission of sulfurtrioxide, the method comprising routing a first relief conduit so as toprovide a first route of fluid communication between a first pressurizedvessel and a relief vessel, wherein the first pressurized vesselcontains sulfur trioxide, wherein the relief vessel contains a volume ofa solvent solution, and wherein the solvent solution comprisessulfolane.

Further disclosed herein is a method for containing an emission ofsulfur trioxide, the method comprising directing an emission of sulfurtrioxide from a first pressurized vessel to a relief vessel via a firstrelief conduit, wherein the relief vessel contains a volume of a solventsolution, comprising sulfolane, and forming an emission mixturecomprising sulfur trioxide dissolved in sulfolane within the reliefvessel.

BRIEF DESCRIPTION OF THE DRAWINGS

For a more complete understanding of the present disclosure and theadvantages thereof, reference is now made to the following briefdescription, taken in connection with the accompanying drawings anddetailed description, wherein like reference numerals represent likeparts.

FIG. 1 illustrates an embodiment of a sulfur trioxide emissioncontainment system;

FIG. 2 illustrates an embodiment of a relief vessel; and

FIG. 3 illustrates an embodiment of sulfur trioxide emission containmentmethod.

DETAILED DESCRIPTION

Disclosed herein are systems and methods for containing an emission ofsulfur trioxide (SO₃). The disclosed embodiments of a sulfur trioxideemission containment (STEC) system and associated method are usefulwhere sulfur trioxide is employed as an input to an industrial process(for example, as a process reactant); where SO₃ is an output from anindustrial process (for example, where sulfur trioxide is a processproduct or where excess, unreacted sulfur trioxide remains); and/orwhere sulfur trioxide is stored (for example, in a storage facility) ortransported (for example, by truck or rail-car).

Referring to FIG. 1, an exemplary STEC system 100 in accordance withembodiments of the present disclosure is illustrated. The STEC system100 as shown in FIG. 1 represents an industrial setting, for example, anindustrial environment in which sulfur trioxide is present (e.g., usedas a reactant) in an industrial process. For example, STEC system 100 ofFIG. 1 can be an industrial plant (e.g., a production facility) of thetype used to produce a sulfated or sulfonated end-product. Examples ofsuch industrial facilities include plants for the production ofsulfonated asphalt and plants for the production of surfactantcompositions, such as those used in shampoos, detergents, or the like.In alternative embodiments, as will be disclosed herein, an otherwisesimilar STEC system can be similarly employed in any suitable setting orenvironment where sulfur trioxide is used or is otherwise present.Examples of such environments include the production of sulfonic and/orsulfuric acid, the production of catalyst(s), specific refiningapplications, flue gas emissions produced during the burning of coal orother fossil fuels.

Generally, in accordance with the instant disclosure, an STEC systemcomprises a sulfur trioxide source, a relief vessel containing a solventsolution, and a relief conduit providing a route of fluid communicationfrom the sulfur trioxide source to the relief vessel. As used herein, asulfur trioxide source refers to a point at which sulfur trioxide can bestored, input into a system, used within a system, output or withdrawnfrom a system, or any other point within a system from which sulfurtrioxide can be collected or output. While one or more of theembodiments disclosed herein can illustrate particular sources of sulfurtrioxide, the person of ordinary skill in the art will, upon review ofthis disclosure, recognize that sulfur trioxide can be similarlycollected, contained, or output from any number or combination of sulfurtrioxide sources.

Referring again to the embodiment of FIG. 1, the STEC system 100comprises a first sulfur trioxide source that is a storage vessel 120, asecond sulfur trioxide source that is a reactor 130, a third sulfurtrioxide source that is an output conduit 140, a relief vessel 200containing a solvent solution, a first relief conduit 160, a secondrelief conduit 170, and a third relief conduit 180. While the embodimentof FIG. 1 illustrates a first, second, and third sulfur trioxide sources(e.g., storage vessel 120, reactor 130, and output conduit 140), inadditional or alternative embodiments, an otherwise similar STEC systemcan include any one or additional sulfur trioxide sources.

In the embodiment of FIG. 1, the storage vessel 120 (that is, the firstsulfur trioxide source) contains a volume of sulfur trioxide. Thestorage vessel 120 can comprise a permanent or semi-permanent fixture atthe site of the STEC system 100, for example, a tank or tank battery, orthe like. Alternatively, the storage vessel 120 can comprise a mobile ormovable vessel, for example a rail-car container, a trailer container, atote, a skid-mounted container, or the like. The storage vessel 120 canhave any suitable volume, for example and without limitation, about1,000 gallons (3800 liters), alternatively, about 2,500 gal. (9500liters), alternatively, about 5,000 gal. (19,000 liters), alternatively,about 10,000 gal. (38,000 liters), alternatively, about 15,000 gal.(57,000 liters), alternatively, about 20,000 gal. (76,000 liters),alternatively, about 25,000 gal. (95,000 liters), alternatively, about30,000 gal. (114,000 liters), alternatively, about 35,000 gal. (133,000liters) (e.g., a rail-car, having a maximum capacity of about 34,500gal. (131,000 liters)), as well as volumes between any two of thesesuitable volumes, e.g., about 12,500 gal. (47,000 liters).

In the embodiment of FIG. 1, the storage vessel 120 comprises a heatingelement 122. Because sulfur trioxide exhibits a freezing/meltingtemperature of about 62.4° F. (16.9° C.), the heating element 122 can beprovided for the purpose of maintaining the sulfur trioxide in liquid ora substantially liquid state, for example, such that the volume ofsulfur trioxide stored in the storage vessel 120 remains sufficientlyfree-flowing. The heating element can be conventional, for example, ametallic element, a ceramic element, a composite element, or the like,as well as combinations thereof, and can be sized accordingly to thevolume of the storage vessel and/or the desired temperature to bemaintained.

With continued reference to the embodiment of FIG. 1, the storage vessel120 further comprises a vent 124. For example, the vent 124 can beprovided for the purpose of ensuring that a safe or desired internalpressure is not exceeded (e.g., a pressure relief vent). By way offurther example, heating the volume of sulfur trioxide stored in thestorage vessel and/or changes in environmental conditions can contributeto a rise in the internal pressure of the storage vessel 120. Also, inan embodiment, the vent 124 can include a pressure relief valve 126, forexample, configured to allow pressure within the storage vessel toescape when a particular pressure threshold is exceeded. In such anembodiment, the pressure relief valve can be configured to actuate(e.g., to allow pressure to be released) at a pressure of at least about5 pounds per square inch (p.s.i. or 34.5 kilopascals), alternatively,about 10 p.s.i. (69 kPa), alternatively, about 15 p.s.i. (103 kPa),alternatively, about 20 p.s.i. (138 kPa), alternatively, about 25 p.s.i.(172 kPa), alternatively, about 30 p.s.i. (207 kPa), alternatively,about 40 p.s.i. (276 kPa), alternatively, about 50 p.s.i (345 kPa).

In the embodiment of FIG. 1, the reactor 130, can be any suitablereactor, for example, a chemical reactor generally configured to containand/control a chemical reaction, for example, a sulfurization reaction.The reactor 130 can comprise any suitable type or configuration ofchemical reactor, for example, to accommodate two or more reactants,catalysts, solvents, and/or inert materials and to allow for the controlof various process variables including residence time, temperature,pressure, concentration of the reactants and/or products, andcombinations thereof. For example, the reactor 130 can comprise a tankconfiguration or a pipe/tubular configuration (e.g., a “loop” reactor).In various embodiments, the reactor 130 can be operated in accordancewith a batch reactor model, a continuous stirred-tank reactor model, ora plug flow reactor model.

In the embodiment of FIG. 1, the reactor 130 receives sulfur trioxidefrom the storage vessel 120 for use as a reactant. The reactor 130 canreceive additional chemical reactants by way of other or separatereactant and/or reagent transfer lines (not shown) from various othersources (e.g., asphalt, alcohols, ethoxylated alcohols, brightstock, oralkyl benzene), as suitable for the chemical reaction being carried outwithin the reactor 130.

The reactor 130, similar to the storage vessel 120, can comprise a vent134 for the purpose of ensuring that a safe or desired internal pressurewithin reactor 130 is not exceeded. Also, in an embodiment, the vent 134can include a pressure relief valve 136 configured to allow pressurewithin the reactor 130 to escape when a particular pressure threshold isexceeded.

Following residence within reactor 130, the reactor 130 outputs aneffluent or output stream 138 comprising product and various unreactedcomponents (e.g., excess reactants, solvents, inert materials, orcatalysts) that is conveyed away from the reactor, for example, forfurther processing. For example, in the embodiment of FIG. 1, the outputstream 138 is directed to a separation unit 139 configured to separatethe product (e.g., sulfonated asphalt, alcohol sulfuric acid, alkylbenzene sulfonic acid, petroleum sulfonates, or oleum) from some or allof the unreacted components. The separation unit 139 can comprise anysuitable type or configuration of one or more separation units dependentupon the product and unreacted components being separated. Examples ofseparation units include, but are not limited todistillation/fractionation columns, settling tanks, cyclonic separators,filtration units, centrifugation systems, electrostatic precipitationunits, or the like. In the embodiment of FIG. 1, the separation unit 139separates the output stream 138 into an unreacted component stream thatis conveyed away from the separation unit 139 via the output conduit 140(e.g., a “top stream” or “side stream”) and a product stream that isconveyed away from the separation unit 139 via a product conduit 145(e.g., a “bottoms stream”). In the embodiment of FIG. 1, the unreactedcomponent stream within the output conduit 140 comprises sulfur trioxide(e.g., unreacted sulfur trioxide from the reactor 130) and, as such, atleast a portion of this stream can be directed to the relief vessel 200,as will be detailed herein. In an alternative embodiment, all or aportion of any stream comprising sulfur trioxide can be similarlyconveyed to the relief vessel 200 by any number of conveyance means,including fluid transfer lines and the like. Also, while the embodimentof FIG. 1 illustrates only a single separation unit 139, in additionalor alternative embodiments, any suitable number and arrangement ofseparation units can be employed, for example, to separate a particularstream (e.g., a stream output by a reactor or by another separationunit) into two or more substituent components.

Referring again to the embodiment of FIG. 1, the first relief conduit160 provides a route of fluid communication between the vent 124 of thestorage vessel 120 and the relief vessel 200. Similarly, in theembodiment of FIG. 1, the second relief conduit 170 provides a route offluid communication between the vent 134 of the reactor 130 and therelief vessel 200, and the third relief conduit 180 provides a route offluid communication between the output conduit 140 and the relief vessel200. The first relief conduit 160, the second relief conduit 170, andthe third relief conduit 180 can each, independently, comprise anysuitable type, configuration, and size of conduit generally configuredto provide fluid communication, as disclosed herein. Examples ofsuitable conduits include, but are not limited to, pipe or tubing formedfrom one or more materials such as ceramics, glass, fiberglass, metalsand alloys thereof, concrete, and combinations thereof.

The embodiment of FIG. 1 illustrates each of the first relief conduit160, the second relief conduit 170, and the third relief conduit 180being directed to a single relief vessel (i.e., relief vessel 200); thatis relief conduits from multiple sources are directed to a single reliefvessel. In additional or alternative embodiments, each relief conduitfrom each single given source of sulfur trioxide can be directed to adesignated, counterpart single relief vessel; alternatively, reliefconduits from a single particular source of sulfur trioxide can bedirected to multiple relief vessels (e.g., two, three, four, or fiverelief vessels); or combinations thereof. Also, and as previously noted,while the embodiment of FIG. 1 illustrates particular sources of sulfurtrioxide (i.e., the storage vessel 120, the reactor 130, and the outputconduit 140), any point within a STEC system (e.g., like STEC system100) from which sulfur trioxide is present can serve as a sulfurtrioxide source and, in such an embodiment, one or more additionalconduits can be similarly configured to direct a volume of sulfurtrioxide to a relief vessel like relief vessel 200.

Referring to FIG. 2, details of an embodiment of an exemplary reliefvessel 200 is illustrated. In the embodiment of FIG. 2, the reliefvessel 200 generally comprises a permanent or semi-permanent fixture atthe site of the STEC system 100, for example, a tank or tank battery, orthe like. Alternatively, the relief vessel 200 can comprise a mobile ormovable vessel, for example a rail-car container, a trailer container, atote, a skid-mounted container, or the like. In the embodiment of FIG.2, the relief vessel 200 is fully enclosed. Alternatively, the reliefvessel 200 is substantially or partially enclosed. Additionally, in anembodiment, the relief vessel 200 can comprise one or more vents, forexample, for the purpose of regulating pressure within the relief vessel200.

In the embodiment of FIG. 2, the relief vessel 200 retains a volume of asolvent solution 201 within its wall or walls 202. The relief vessel 200can be sized to retain both the volume of solvent solution and a volumeof sulfur trioxide, for example, a volume of sulfur trioxide as can beanticipated to be collected from one or more of the sources of sulfurtrioxide (e.g., the storage vessel 120, the reactor 130, and the outputconduit 140).

In an embodiment of the present disclosure, the solvent solution 201comprises sulfolane (tetramethylene sulfone; tetrahydrothiophene1,1-dioxide; or 2,3,4,5-tetrahydrothiophene-1,1-dioxide). Sulfolane isan organosulfur compound having formula (CH₂)₃SO₄ and shown below ascompound (I):

In an embodiment, the solvent solution comprises at least 60%, byweight, sulfolane, alternatively, at least 70 wt. %, alternatively, atleast 80 wt. %, alternatively, at least 90 wt. %, alternatively, atleast 95 wt. %, alternatively, at least 96 wt. %, alternatively, atleast 97 wt. %, alternatively, at least 97.5 wt. %, alternatively, atleast 98 wt. %, alternatively, at least 98.5 wt. %, alternatively, atleast 99.0 wt. %, alternatively, at least 99.1 wt. %, alternatively, atleast 99.2 wt. %, alternatively, at least 99.3 wt. %, alternatively, atleast 99.4 wt. %, alternatively, at least 99.5 wt. %, alternatively, atleast 99.6 wt. %, alternatively, at least 99.7 wt. %, alternatively, atleast 99.8 wt. %, alternatively, at least 99.9 wt. %, alternatively, atleast 99.95 wt. % sulfolane.

In an embodiment, the sulfolane present within the solvent solution canbe effective to absorb a volume of sulfur trioxide introduced into thesolvent solution. That is, a volume of sulfur trioxide introduced intothe sulfolane-containing solvent solution can be sequestered (e.g.,absorbed by) without reacting with the sulfolane. For example, and againnot intending to be bound by theory, sulfolane can be effective tosequester (e.g., absorb) about 30 mol. % of sulfur trioxide therein.

In an embodiment, the solvent solution can further comprise water. Forexample, the solvent solution can comprise about 0.5 wt. % water,alternatively, about 1.0 wt. % water, alternatively, about 1.5 wt. %water, alternatively, about 2.0 wt. % water, alternatively, about 2.5wt. % water, alternatively, about 3.0 wt. % water. Not intending to bebound by theory, inclusion of water (e.g., a relatively small percentageof water) within the sulfolane-containing solvent solution can beeffective to improve one or more operational parameters of the solventsolution. For example, inclusion of water within thesulfolane-containing solvent solution can be effective to depress thefreezing point of the sulfolane and/or to improve the loadingcapabilities of the sulfolane. For instance, a solvent solutioncontaining sulfolane and about 3 wt. % of water can exhibit an increasein sulfur trioxide loading capacity (e.g., absorption) of about 5%(e.g., about 35 mol. % of sulfur trioxide can be dissolved therein).

In an embodiment, the solvent solution comprises one or more additives.Examples of such additives include but are not limited to linear alkanehydrocarbons preferably in the C10-C14 range or isoparraffins in theC12-C18 range. In an embodiment where an additive is present, theadditive can be present in an amount sufficient to yield a desiredeffect, for example, as can be dependent upon the additive and/or itsdesired effect within the solvent solution. In an embodiment, thesolvent solution further comprises a dispersed fluid, for example, avolume of a fluid dispersed within the sulfolane. In such an embodiment,the dispersed fluid comprises an organic compound, examples of whichinclude linear alkane hydrocarbons preferably in the C10-C14 range orisoparraffins in the C12-C18 range. In an embodiment where the solventsolution comprises a dispersed fluid, the dispersed fluid can be presentin a quantum sufficient (e.g., q.s.) amount to yield a solvent solutioncomprising sulfolane, water, and/or additives present in a desiredpercentage (e.g., as disclosed herein). For example, the solventsolution can comprise about 30%, by weight, dispersed fluid,alternatively, about 20 wt. %, alternatively, about 10 wt. %,alternatively, about 5 wt. %, alternatively, about 2.5 wt. %,alternatively, about 2 wt. %, alternatively, about 1 wt. %,alternatively, less than 1 wt. %.

Referring again to FIG. 2, the relief vessel 200 is configured tocollect sulfur trioxide from one or more sulfur trioxide sources. Forexample, in the embodiment of FIG. 2 the first relief conduit 160, thesecond relief conduit 170, and the third relief conduit 180 are receivedby the relief vessel 200 via a common input conduit 210 (e.g., amanifold).

In an embodiment, the relief vessel 200 can be configured to encouragedissipation of a volume of sulfur trioxide in the solvent solutionretained therein. For example, in the embodiment of FIG. 2, the sulfurtrioxide is introduced into the relief vessel 200 via a bubbler 220, forexample, having a plurality of holes 225 to encourage dispersion of thesulfur trioxide in the solvent solution. The bubbler 220 can be of anysuitable size and shape such as one or more rods, a circular pan, andthe like. In additional embodiments, the relief vessel can comprise, forexample, a circulatory pump (not shown) to encourage dispersion of thesulfur trioxide in the solvent solution.

Referring again to the embodiment of FIG. 1, the STEC system 100 canfurther comprise a solvent regeneration system 190. The solventregeneration system is generally configured to provide an environment inwhich a solvent solution having sulfur trioxide dissolved therein (e.g.,an “emission mixture”) may be regenerated to form a usable solventsolution. The STEC system 100 further comprises an emission mixtureconduit 191 and a regenerated solvent solution conduit 192, providingroutes of fluid communication from the relief vessel 200 to the solventregeneration system 190 and from the solvent regeneration system 190 tothe relief vessel 200.

Also disclosed herein are methods of containing an emission of sulfurtrioxide. For example, referring to FIG. 3, an embodiment of STEC method300 is illustrated graphically.

In the embodiment of FIG. 3, the STEC method 300 comprises a step 310 ofproviding a route of fluid communication from at least one sulfurtrioxide source to a relief vessel. For example, in the context of theembodiment of FIG. 1, as previously disclosed herein, a route of fluidcommunication (e.g., the first relief conduit 160, the second reliefconduit 170, and the third relief conduit 180) is provided from each ofthree sources of sulfur trioxide (e.g., the storage vessel 120, thereactor 130, and the output conduit 140) to the relief vessel 200. Inalternative embodiments, and as previously noted, the sulfur trioxidesource can comprise any point at which sulfur trioxide is present withina system. For example, in the context of a laboratory environment, thesulfur trioxide source can comprise a fume hood.

Referring again to the embodiment of FIG. 3, the STEC method 300 alsocomprises a step 320 of maintaining a volume of the solvent solutionwithin the relief vessel. As previously disclosed herein, the solventsolution can comprise sulfolane and, optionally, water. As will befurther described herein, providing the route of fluid communicationfrom the at least one sulfur trioxide source to the relief vessel andmaintaining the volume of the solvent solution within the relief vesselenables an emission of sulfur trioxide to be collected and controlled,as will be disclosed herein.). The solvent solution can be maintained ata suitable temperature and pressure. In an embodiment, the solventsolution is maintained at about atmospheric pressure and at atemperature that is about the freezing point of the solvent solution(e.g., sulfolane or the water sulfolane mixture, or theparraffin-sulfolane dispersion).

Additionally, in the embodiment of FIG. 3, the STEC method 300 comprisesthe step 330 of operating the system (e.g., the overall system of whichthe STEC system is a part such as an asphalt sulfonation unit) for itsintended purpose. For example, in the embodiment of FIG. 1, the STECsystem 100 comprises an industrial setting 102, for example, anindustrial environment in which sulfur trioxide is present (e.g., usedas a reactant) in an industrial process. In such an embodiment,operating the system can comprise transferring the sulfur trioxide fromthe first storage vessel to the reactor, forming a reaction mixturecomprising the sulfur trioxide and a second reactant (e.g., asphalt, inan embodiment where the system is for the purpose of producingsulfonated asphalt), and reacting the sulfur trioxide with the secondreactant (e.g., the asphalt) to yield a desired product (e.g.,sulfonated asphalt).

In another embodiment where the STEC system comprises, as an example, alaboratory setting, for example, where sulfur trioxide source cancomprise a fume hood, operating the system can comprise operating thefume hood, for example, to evacuate a volume of air having orpotentially having sulfur trioxide.

As will be appreciate by the person of ordinary skill in the art uponviewing this disclosure, the operation of various systems where sulfurtrioxide is present can result in various emissions or point sources ofsulfur trioxide. Some emissions of sulfur trioxide can be expected whileothers can be unexpected. For example, referring to the embodiment ofFIG. 3, an emission of sulfur trioxide from the storage vessel 120 orthe reactor 130 can unexpectedly result from the normal operation ofSTEC system 100. For example, the storage vessel 120 can unexpectedlyemit sulfur trioxide (e.g., via vent 124) upon an over-pressuring of thestorage vessel 120 or a malfunction of the pressure relief valve 126 orthe heating element 122 (e.g., where the heating element causes thesulfur trioxide within the storage vessel 120 to overheat). Similarly,the reactor 130 can unexpectedly emit sulfur trioxide upon anover-pressuring or other operating upset of the reactor 130.

Alternatively, an emission of sulfur trioxide via the output conduit 140can be expected. For example, in some embodiments where sulfur trioxideis employed as a reactant, at least some excess sulfur trioxide can beemitted from the reactor 130 and, as such, can be collected during thenormal operation of the system. In such embodiments, the relief vessel200 can serve as emissions control equipment, such as an off gasscrubber.

Referring again to the embodiment of FIG. 3, the STEC method 300 furthercomprises a step 340 of directing an emission of sulfur trioxide fromthe sulfur trioxide source to the relief vessel. For example, andreferring to the embodiment of FIG. 1, where sulfur trioxide is emitted,whether expectedly or unexpectedly, the emission of sulfur trioxide canbe collected from the storage vessel 120 (e.g., via the vent 124) anddirected to the relief vessel 200 via the first relief conduit 160,additionally or alternatively, from the reactor 130 (e.g., via the vent134) and directed to the relief vessel 200 via the second relief conduit170, additionally or alternatively, from the output conduit 140 anddirected to the relief vessel 200 via the third relief conduit 180.

With continued reference to FIG. 3, the STEC method 300 furthercomprises the step 350 of forming an emission mixture within the reliefvessel. For example, referring again to the embodiment of FIGS. 1 and 2,the sulfur trioxide is introduced into the relief vessel 200 (e.g., fromthe first relief conduit 160, the second relief conduit 170, and/or thethird relief conduit 180) via the common input conduit (e.g., a manifold210) and disperses within the solvent solution 201 retained within therelief vessel 200, thereby forming the emission mixture. In anembodiment, the sulfur trioxide is introduced (e.g., dispersed) withinthe solvent solution via the bubbler 220. The solvent solution can beeffective to sequester an amount of sulfur trioxide; for example, thesulfolane can be effective to absorb an amount of sulfur trioxide. Forexample, the emission mixture formed within the relief vessel 200 cancomprise sulfur trioxide dissolved in (e.g., absorbed by) sulfolanewithin the relief vessel. In an embodiment, the emission mixture formedwithin the relief vessel 200 comprises up to about 30 mol. % of sulfurtrioxide to be dissolved therein, alternatively, up to about 31 mol. %of sulfur trioxide, alternatively, up to about 32 mol. % of sulfurtrioxide, alternatively, up to about 33 mol. % of sulfur trioxide,alternatively, up to about 34 mol. % of sulfur trioxide, alternatively,up to about 35 mol. % of sulfur trioxide. For instance, for each mole ofsulfolane in the solvent solution, the solvent solution can be effectiveto absorb about 0.30 moles of sulfur trioxide, alternatively, about 0.31moles of sulfur trioxide, alternatively, about 0.32 moles of sulfurtrioxide, alternatively, about 0.33 moles of sulfur trioxide,alternatively, about 0.34 moles of sulfur trioxide, alternatively, about0.35 moles of sulfur trioxide.

The STEC method 300 further comprises a step 360 of reforming thesolvent solution. In accordance with this process or method, reformingthe solvent solution comprises adding water to the emission mixture.Referring again to FIG. 1, the emission mixture can be conveyed to thesolvent regeneration system 190, for example, via the emission mixtureconduit 191. In an embodiment, water added to the emission mixture canreact with the sulfur trioxide dissolved therein to form sulfuric acid.The reaction between sulfur trioxide and water can be highly exothermicand, as such, the water added to the emission mixture can be addedslowly over an extended period of time and in a controlled manner, forexample, to allow the heat produced by the reaction to dissipate. Thesulfuric acid resulting from the reaction can remain dissolved in thesolvent solution (e.g., in the sulfolane). The sulfolane can beregenerated at a later point, for example, via a distillation, aback-extraction, adsorption, or counter-ion exchange column. Theregenerated sulfolane can then be returned or recycled back to therelief vessel 200, for example, via the regenerated solvent solutionconduit 192, to further absorb any additional release of sulfurtrioxide.

ADDITIONAL EMBODIMENTS

A first embodiment, which is a system for containing an emission ofsulfur trioxide, the system comprising a first pressurized vessel, thefirst pressurized vessel containing sulfur trioxide; a relief vesselcontaining a volume of a solvent solution, wherein the solvent solutioncomprises sulfolane; and a first relief conduit providing a first routeof fluid communication between the first pressurized vessel and therelief vessel.

A second embodiment, which is the system of the first embodiment,wherein the first pressurized vessel is a storage vessel.

A third embodiment, which is the system of one of first through thesecond embodiments, wherein the storage vessel includes an internalheating element configured to heat the sulfur trioxide.

A fourth embodiment, which is the system of one of first through thethird embodiments, further comprising a second pressurized vessel; and asecond relief conduit providing a second route of fluid communicationbetween the second pressurized vessel and the relief vessel.

A fifth embodiment, which is the system of the fourth embodiment,wherein the second pressurized vessel is a reactor, wherein the reactorcontains a reaction mixture.

A sixth embodiment, which is the system of the fifth embodiment, whereinthe reaction mixture comprises sulfur trioxide and asphalt.

A seventh embodiment, which is the system of one of the first throughthe sixth embodiments, wherein the first pressurized vessel is areactor, and wherein the sulfur trioxide within the reactor is acomponent of a reaction mixture contained within the reactor.

An eighth embodiment, which is the system of the seventh embodiment,wherein the reaction mixture further comprises asphalt.

A ninth embodiment, which is the system of one of the first through theeighth embodiments, wherein the solvent solution further compriseswater.

A tenth embodiment, which is the system of the ninth embodiment, whereinthe solvent solution further comprises at least 1 weight % water on thebasis of the sulfolane.

An eleventh embodiment, which is the system of the ninth embodiment,wherein the solvent solution further comprises at least 2 weight % wateron the basis of the sulfolane.

A twelfth embodiment, which is the system of the ninth embodiment,wherein the solvent solution further comprises at least 3 weight % wateron the basis of the sulfolane.

A thirteenth embodiment, which is the system of one of the first throughthe twelfth embodiments, further comprising a pressure relief valve,wherein the pressure relief valve controls fluid communication via thefirst route of fluid communication between the first pressurized vesseland the relief vessel.

A fourteenth embodiment, which is a method for containing an emission ofsulfur trioxide, the method comprising routing a first relief conduit soas to provide a first route of fluid communication between a firstpressurized vessel and a relief vessel, wherein the first pressurizedvessel contains sulfur trioxide, wherein the relief vessel contains avolume of a solvent solution, and wherein the solvent solution comprisessulfolane.

A fifteenth embodiment, which is the method of the fourteenthembodiment, wherein the first pressurized vessel is a storage vessel.

A sixteenth embodiment, which is the method of the fifteenth embodiment,wherein the storage vessel includes an internal heating elementconfigured to heat the sulfur trioxide.

A seventeenth embodiment, which is the method of one of the fourteenththrough the sixteenth embodiments, further comprising routing a secondrelief conduit so as to provide a second route of fluid communicationbetween a second pressurized vessel and the relief vessel, wherein thesecond pressurized vessel contains sulfur trioxide.

An eighteenth embodiment, which is the method of the seventeenthembodiment, wherein the second pressurized vessel is a reactor, andwherein the method further comprises communicating the sulfur trioxidefrom the first storage vessel to the reactor.

A nineteenth embodiment, which is the method of the eighteenthembodiment, further comprising introducing asphalt into the reactor.

A twentieth embodiment, which is the method of the nineteenthembodiment, further comprising forming a reaction mixture comprising thesulfur trioxide and the asphalt; and reacting the sulfur trioxide withthe asphalt to yield a sulfonated asphalt.

A twenty-first embodiment, which is the method of one of the fourteenththrough the twentieth embodiments, wherein the first pressurized vesselis a reactor, and wherein the sulfur trioxide within the reactor is acomponent of a reaction mixture contained within the reactor.

A twenty-second embodiment, which is the method of the twenty-firstembodiment, wherein the reaction mixture further comprises asphalt.

A twenty-third embodiment, which is the method of the twenty-secondembodiment, further comprising forming a reaction mixture comprising thesulfur trioxide and the asphalt; and reacting the sulfur trioxide withthe asphalt to yield a sulfonated asphalt.

A twenty-fourth embodiment, which is the method of one of the fourteenththrough the twenty-third embodiments, wherein the solvent solutionfurther comprises water.

A twenty-fifth embodiment, which is the method of the twenty-fourthembodiment, wherein the solvent solution further comprises at least 1weight % water on the basis of the sulfolane.

A twenty-sixth embodiment, which is the method of the twenty-fourthembodiment, wherein the solvent solution further comprises at least 2weight % water on the basis of the sulfolane.

A twenty-seventh embodiment, which is the method of the twenty-fourthembodiment, wherein the solvent solution further comprises at least 3weight % water on the basis of the sulfolane.

A twenty-eighth embodiment, which is the method of one of the fourteenththrough the twenty-seventh embodiments, further comprising controllingfluid communication via the first route of fluid communication betweenthe first pressurized vessel and the relief vessel via a pressure reliefvalve.

A twenty-ninth embodiment, which is a method for containing an emissionof sulfur trioxide, the method comprising directing an emission ofsulfur trioxide from a first pressurized vessel to a relief vessel via afirst relief conduit, wherein the relief vessel contains a volume of asolvent solution, comprising sulfolane; and forming an emission mixturecomprising sulfur trioxide dissolved in sulfolane within the reliefvessel.

A thirtieth embodiment, which is the method of the twenty-ninthembodiment, wherein the first pressurized vessel is a storage vessel.

A thirty-first embodiment, which is the method of the thirtiethembodiment, further comprising heating the sulfur trioxide via aninternal heating element within the storage vessel.

A thirty-second embodiment, which is the method of one of thetwenty-ninth through the thirty-first embodiments, wherein the firstpressurized vessel is a reactor, wherein the sulfur trioxide within thereactor is a component of a reaction mixture contained within thereactor.

A thirty-third embodiment, which is the method of the thirty-secondembodiment, further comprising introducing asphalt into the reactor.

A thirty-fourth embodiment, which is the method of the thirty-thirdembodiment, further comprising forming the reaction mixture, wherein thereaction mixture comprises the sulfur trioxide and the asphalt; andreacting the sulfur trioxide with the asphalt to yield a sulfonatedasphalt.

A thirty-fifth embodiment, which is the method of one of thetwenty-ninth through the thirty-fourth embodiments, wherein the solventsolution further comprises water.

A thirty-sixth embodiment, which is the method of the thirty-fifthembodiment, wherein the solvent solution further comprises at least 1weight % water on the basis of the sulfolane.

A thirty-seventh embodiment, which is the method of the thirty-fifthembodiment, wherein the solvent solution further comprises at least 2weight % water on the basis of the sulfolane.

A thirty-eighth embodiment, which is the method of the thirty-fifthembodiment, wherein the solvent solution further comprises at least 3weight % water on the basis of the sulfolane.

A thirty-ninth embodiment, which is the method of one of thetwenty-ninth through the thirty-eighth embodiments, further comprisingadding water to the emission mixture.

A fortieth embodiment, which is the method of one of the twenty-ninththrough the thirty-ninth embodiments, wherein the emission of sulfurtrioxide from the first pressurized vessel to the relief vessel via thefirst relief conduit is allowed via operation of a pressure reliefvalve.

A forty-first embodiment, which is a method for containing an emissionof sulfur trioxide, the method comprising directing an emissioncomprising sulfur trioxide to a relief vessel, wherein the relief vesselcontains a volume of a solvent solution, and wherein the solventsolution comprises sulfolane; and forming an emission mixture comprisingsulfur trioxide dissolved in sulfolane within the relief vessel.

A forty-second embodiment, which is the method of the forty-firstembodiment, wherein the emission comprising sulfur trioxide is capturedfrom a first pressurized vessel.

A forty-third embodiment, which is the method of the forty-secondembodiment, wherein the first pressurized vessel is a storage vessel.

A forty-fourth embodiment, which is the method of the forty-thirdembodiment, further comprising heating the sulfur trioxide via aninternal heating element within the storage vessel.

A forty-fifth embodiment, which is the method of one of the forty-secondthrough the forty-fourth embodiments, wherein the first pressurizedvessel is a reactor, and wherein the sulfur trioxide within the reactoris a component of a reaction mixture contained within the reactor.

A forty-sixth embodiment, which is the method of one of the forty-firstthrough the forty-fifth embodiments, wherein the solvent solutionfurther comprises water.

A forty-seventh embodiment, which is the method of the forty-sixthembodiment, wherein the solvent solution further comprises at least 1weight % water on the basis of the sulfolane.

A forty-eighth embodiment, which is the method of claim the forty-sixthembodiment, wherein the solvent solution further comprises at least 2weight % water on the basis of the sulfolane.

A forty-ninth embodiment, which is the method of the forty-sixthembodiment, wherein the solvent solution further comprises at least 3weight % water on the basis of the sulfolane.

A fiftieth embodiment, which is the method of one of the forty-firstthrough the forty-ninth embodiments, further comprising adding water tothe emission mixture.

A fifty-first embodiment, which is the method of fiftieth embodiment,further comprising regenerating the solvent solution from the emissionmixture, wherein regenerating the solvent solution comprises removingsulfuric acid from the emission mixture after adding water to theemission mixture.

A fifty-second embodiment, which is the method of fifty-firstembodiment, further comprising retaining the regenerated solventsolution in a relief vessel.

While embodiments of the disclosure have been shown and described,modifications thereof can be made without departing from the spirit andteachings of the invention. The embodiments and examples describedherein are exemplary only, and are not intended to be limiting. Manyvariations and modifications of the invention disclosed herein arepossible and are within the scope of the invention.

At least one embodiment is disclosed and variations, combinations,and/or modifications of the embodiment(s) and/or features of theembodiment(s) made by a person having ordinary skill in the art arewithin the scope of the disclosure. Alternative embodiments that resultfrom combining, integrating, and/or omitting features of theembodiment(s) are also within the scope of the disclosure. Wherenumerical ranges or limitations are expressly stated, such expressranges or limitations should be understood to include iterative rangesor limitations of like magnitude falling within the expressly statedranges or limitations (e.g., includes, for example, from about 1 toabout 10 includes, 2, 3, 4 greater than 0.10 includes 0.11, 0.12, 0.13).For example, whenever a numerical range with a lower limit, R_(l), andan upper limit, R_(u), is disclosed, any number falling within the rangeis specifically disclosed. In particular, the following numbers withinthe range are specifically disclosed: R=R_(l)+k*(R_(u)−R_(l)), wherein kis a variable ranging from 1 percent to 100 percent with a 1 percentincrement, i.e., k is 1 percent, 2 percent, 3 percent, 4 percent, 5percent, . . . 50 percent, 51 percent, 52 percent . . . 95 percent, 96percent, 97 percent, 98 percent, 99 percent, or 100 percent. Moreover,any numerical range defined by two R numbers as defined in the above isalso specifically disclosed. Use of the term “optionally” with respectto any element of a claim means that the element is required, oralternatively, the element is not required, both alternatives beingwithin the scope of the claim. Use of broader terms such as comprises,includes, and having should be understood to provide support fornarrower terms such as consisting of, consisting essentially of, andcomprised substantially of.

Each and every claim is incorporated into the specification as anembodiment of the present invention. Thus, the claims are a furtherdescription and are an addition to the detailed description of thepresent invention.

What is claimed is:
 1. A method for containing an emission of sulfurtrioxide, the method comprising: routing a first relief conduit so as toprovide a first route of fluid communication between a first pressurizedvessel and a relief vessel, wherein the first pressurized vessel is afirst reactor and contains sulfur trioxide that is a component of areaction mixture contained within the first reactor, wherein the reliefvessel contains a volume of a solvent solution, and wherein the solventsolution comprises sulfolane and up to 3 wt % water on a basis of thesulfolane; and introducing asphalt into the first reactor.
 2. The methodof claim 1, wherein the first pressurized vessel is a storage vessel. 3.The method of claim 2, wherein the storage vessel includes an internalheating element configured to heat the sulfur trioxide.
 4. The method ofclaim 2, further comprising: routing a second relief conduit so as toprovide a second route of fluid communication between a secondpressurized vessel and the relief vessel, wherein the second pressurizedvessel contains sulfur trioxide.
 5. The method of claim 4, wherein thesecond pressurized vessel is a second reactor, and wherein the methodfurther comprises communicating the sulfur trioxide from the storagevessel to the second reactor.
 6. The method of claim 1, furthercomprising controlling fluid communication via the first route of fluidcommunication between the first pressurized vessel and the relief vesselvia a pressure relief valve.
 7. The method of claim 1, furthercomprising reacting the sulfur trioxide with the asphalt to yield asulfonated asphalt.
 8. The method of claim 1, further comprisingmaintaining the solvent solution at about atmospheric pressure and at atemperature that is about the freezing point of the solvent solution. 9.A method for containing an emission of sulfur trioxide, the methodcomprising: directing an emission of sulfur trioxide from a firstpressurized vessel to a relief vessel via a first relief conduit,wherein the relief vessel contains a volume of a solvent solutioncomprising sulfolane and up to 3 wt % water on a basis of the sulfolane;forming an emission mixture comprising sulfur trioxide dissolved insulfolane within the relief vessel; and adding water to the emissionmixture.
 10. The method of claim 9, further comprising conveying theemission mixture to a solvent regeneration system.
 11. The method ofclaim 10, wherein the solvent regeneration system is configured toregenerate the sulfolane using at least one of a distillation column, aback-extraction column, an adsorption column, or a counter-ion exchangecolumn.
 12. The method of claim 10, further comprising recycling aregenerated sulfolane effluent from the solvent regeneration system tothe relief vessel.
 13. The method of claim 9, further comprisingregenerating the solvent solution from the emission mixture, whereinregenerating the solvent solution comprises removing sulfuric acid fromthe emission mixture after adding water to the emission mixture.
 14. Themethod of claim 9, wherein the water is added to the emission mixtureover an extended period of time and in a controlled manner to allow heatproduced by an ensuing reaction to dissipate.
 15. A method forcontaining an emission of sulfur trioxide, the method comprising:directing an emission of sulfur trioxide from a first pressurized vesselto a relief vessel via a first relief conduit, wherein the relief vesselcontains a volume of a solvent solution comprising sulfolane and up to 3wt % water on a basis of the sulfolane, and wherein the solvent solutionfurther comprises a dispersed fluid comprising at least one of a linearalkane hydrocarbon in the C₁₀-C₁₄ range or an isoparraffin in theC₁₂-C₁₈ range; and forming an emission mixture comprising sulfurtrioxide dissolved in sulfolane within the relief vessel.
 16. The methodof claim 15, wherein the solvent solution comprises one of 5 wt %dispersed fluid, 2.5 wt % dispersed fluid, 2 wt % dispersed fluid, or 1wt % dispersed fluid.
 17. The method of claim 15, wherein the solventsolution comprises less than about 1 wt % dispersed fluid.
 18. Themethod of claim 15, further comprising conveying the emission mixture toa solvent regeneration system.
 19. A method for containing an emissionof sulfur trioxide, the method comprising: routing a first reliefconduit so as to provide a first route of fluid communication between afirst pressurized vessel and a relief vessel, wherein the firstpressurized vessel is a storage vessel and contains sulfur trioxide,wherein the relief vessel contains a volume of a solvent solution, andwherein the solvent solution comprises sulfolane and up to 3 wt % wateron a basis of the sulfolane; routing a second relief conduit so as toprovide a second route of fluid communication between a secondpressurized vessel and the relief vessel, wherein the second pressurizedvessel contains sulfur trioxide; and wherein sulfur trioxide from thesecond pressurized vessel is routed to the relief vessel via a bubbler.